The Curiosity rover has celebrated its first Martian anniversary, having spent 687 Earth days there since its landing in August 2012.

Sent there to search for evidence of past microbial life, the rover has already discovered that there was once water on Mars from evidence in the samples that it has drilled out of rocks in different locations.

It has travelled a total of 4.9 miles from the landing site in Gale Crater, named Bradbury landing in honour of the science fiction writer Ray Bradbury, towards its final destination of Mount Sharp, where it will examine the geological layers that are visible.

The drives have not been without incident, some unexpected sharp rocks causing wheel damage and prompting the control team to modify the route and the driving methods. "We are getting in some long drives using what we have learned," said Jim Erickson, Curiosity project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "When you're exploring another planet, you expect surprises. The sharp, embedded rocks were a bad surprise."